Grid-tied voltage source inverters using LCL filter have been widely adopted in distributed power generation systems (DPGSs). As high-order LCL filters contain multiple resonant frequencies, switching harmonics generated by the inverter and current harmonics generated by the active/passive loads would cause the system resonance, and thus the output current distortion and oscillation. Such phenomenon is particularly critical when the power grid is weak with the unknown grid impedance. In order to stabilize the operation of the DPGS and improve the waveform of the injected currents, many innovative damping methods have been proposed. A comprehensive overview on those contributions and their classification on the inverter- and grid-side damping measures are presented. Based on the concept of the impedance-based stability analysis, all damping methods can ensure the system stability by modifying the effective output impedance of the inverter or the effective grid impedance. Classical damping methods for industrial applications will be analyzed and compared. Finally, the future trends of the impedance-based stability analysis, as well as some promising damping methods, will be discussed.

/pdf/damping-methods-for-resonances-caused-by-lcl-filter-based-2wxyq1oi9v.pdf

Damping Methods for Resonances Caused by LCL-Filter-Based Current-Controlled Grid-Tied Power Inverters: An Overview

This paper presents a new noninvasive method for calculating utility harmonic impedance at the point of common coupling (PCC). The proposed method is based on a statistical signal-processing technique, known as independent component analysis (ICA). The complex ICA technique is applied to the equations derived from Northon equivalent circuit model at the PCC in order to estimate the utility harmonic current values. Then, the estimated values of the utility harmonic current are used in an optimization problem to calculate the utility harmonic impedance. Due to considering the utility harmonic current variations in utility harmonic impedance calculation, the proposed method is relatively robust against the background harmonic fluctuations. The results obtained from computer simulation and a real case study verify the effectiveness of the proposed method.

A Novel Method for Noninvasive Estimation of Utility Harmonic Impedance Based on Complex Independent Component Analysis

The estimation of the line impedance can be used by the control of numerous grid-connected systems, such as active filters, islanding detection techniques, non-linear current controllers, detection of the on/off grid operation mode Therefore, estimating the line impedance can add extra functions into the operation of the grid-connected power converters This paper describes a quasi-passive method for estimating the line impedance of the distribution electricity network The method uses the model based identification technique to obtain the resistive and inductive parts of the line impedance The quasi-passive behaviour of the proposed method comes from the combination of the non-intrusive behaviour of the passive methods with a better accuracy of the active methods The simulation results reveal the good accuracy of the proposed method

Line impedance estimation using model based identification technique

Grid impedance is one of the most important parameters for operating and controlling of grid-connected converters, especially with the high penetration of renewable energy sources into microgrid and smart grid. One of the technical challenges is how to fast and accurately estimate the grid impedance, even under the distorted and unbalanced conditions. Many impedance estimation methods have been presented in the past decades. Most of them intentionally inject one or more disturbance signals, low frequency or high frequency, to excite the grid response. And then the grid impedance can be estimated by the voltage/current information of two steady-state operating points before and after the disturbance. However, these injected disturbances will deteriorate the power quality. In order to mitigate the problem, a new impedance estimation method is presented in this paper. Its basic idea lies in the inherent switching feature of the grid-connected power converter. Therefore, the grid impedance can be easily estimated with no need of the intentionally injected disturbance signals anymore. The theoretical analysis and performance evaluation results verify the effectiveness of the proposed method.

Real-time grid impedance estimation technique for grid-connected power converters

As the penetration of distributed energy resources based on renewable sources increases, several technical challenges are introduced into energy grids. These include real-time power balance, control of bi-directional energy flow, power quality, distributed optimization, state estimation and topology estimation in distribution grids, and multi-level electricity trading. To overcome these challenges and to create situational awareness in energy grids, pervasive sensing becomes essential. To overcome hurdles such as implementation and cost of such pervasive sensing, in addition to traditional contact-sensing methods, contactless sensors that can measure key variables in the grid needs to be leveraged. Contactless sensing enables measurement of process variables that may be hard to measure due to technological limitations of contact sensing, large measurement delays, or high costs. In addition to contactless sensing, pervasive sensing proves advantageous as it can leverage ongoing technological advances in Internet of Things (IoT), as they can lead to enhanced network connectivity between sensors as well as between the edge and the cloud. Finally, pervasive sensing proves even more attractive by integrating contactless sensing not only with wireless communication but also with shielding and energy harvesting. This paper reviews pervasive sensing techniques in power grids that encompass contactless sensing technologies, IoT connectivity, energy harvesting and shielding. In addition, we also explore how pervasive sensing in a Cyber-Enabled Grid (CEG) can contribute to the development roadmap of Autonomous Energy Grids (AEGs), a futuristic concept where the grid will be making automated operational decisions. The potential challenges and research opportunities in this pioneering research field such as data deluge, cybersecurity, and sensor fusion will be discussed. This review article, which addresses the role of pervasive sensing in CEGs, is a first of its kind. It will help engineers and scientists to understand its significant potential to shape future energy systems.

Cyber-enabled grids: Shaping future energy systems

The new, noninvasive method of measurement for power system harmonic impedance is presented in the paper. The method is based on the observation of variations of voltage and current harmonics caused by natural load variability. The novelty of the method lays in a way the method rejects segments of data containing insufficient or false information about the identified power system. Segment selection/rejection uses logical conditions applied to RMS values of measured voltage and current. Harmonic impedance of the power grid is then calculated using modified power spectral method. The method was validated in a field test conducted at 30 kV feeder bus of HV/MV substation. Details of the experiment and the results are discussed the paper. Obtained results confirm that the method copes with temporal, band-limited excitation as well as with deep, sudden changes of utility background voltage.

http://home.agh.edu.pl/~borkows/uploads/Nauka/2012GM0959_BORKOWSKI.pdf

New method for noninvasive measurement of utility harmonic impedance

The paper concerns important problem: estimation of power system equivalent parameters. Knowledge of these parameters is needed to determine disturbances propagation ability through power grid. Authors present new techniques, which may significantly improve accuracy of noninvasive power system identification. These are: voltage and current coherent resampling algorithm, which ensures that sampling frequency match actual fundamental frequency of power system, so the DFT analysis is almost leakage-free; envelope detection algorithm which allows to estimate equivalent impedance of the load and its variability for fundamental frequency; the method of load change detection ensuring that only fragments having sufficient amount of information for power system identification will be used in parameters estimation. The proposed methods were tested using laboratory power system model of known parameters. Presented results of laboratory experiments confirmed correctness of the described methods.

Estimation of power system parameters based on load variance observations - laboratory studies

This article presents a summary of the development and realization of a custom control and monitoring system for a water supply facility consisting of fixed-capacity intake pumps, a reservoir tank, and variable-speed outtake pumps. Project realization included the design and building of control hardware, as well as the design and deployment of the intake pump switching algorithm. Details of the control system design with an emphasis on the pump switching algorithm are given. The stages of the system development, including process modeling, design goal formulation, optimization of control algorithm using genetic algorithms, simulation, and implementation, are presented. Finally, deployment and real-life results are shown.

Design, optimization, and deployment of a waterworks pumping station control system.

This paper describes a new method of power-grid signal variation measurement, consisting of a demodulation algorithm and a set of measures (indices). The measures that will be presented are the abstract functionals, operating on the complex envelope of a signal. This paper presents a demodulation algorithm, definitions of proposed functionals, results of simulations, as well as laboratory experiments.

New Measures of Power-Grid Voltage Variation

The paper presents an algorithm for detection of a complex envelope of power grid signals. The algorithm is based on a Hilbert transform. It was prepared for an analysis of a low-frequency disturbances, but can also be used as a compex envelope source for other applications. An implementation of the algorithm in a digital signal processor was made to proof an ability of a real-time operation. Analyses with various numerical representations and input signal quantization were done. Execution times on a DSP were measured. Tests proved that the presented algorithm is able to analyze power grid signals in a real-time with satisfying performance and uncertainty.

A Hilbert Transform Based Algorithm for Detection of a Complex Envelope of a Power Grid Signals : an Implementation

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

A. Wetula

Author Tools

Chat about Author